Certain seven conductor electrical connectors for truck-trailer jumper cables have become standard in the industry. A connector which is typical of those in commercial use is shown in my U.S. Pat. No. 5,873,744. Details of a prior art connector assembly for tractor-trailers are disclosed in my U.S. Pat. No. 4,786,261. The connectors are subject to SAE standard J560 b. This standard covers two connectors, the plug and the receptacle. The plugs are normally attached at both ends to a jumper cable. The connectors or receptacles are installed as permanent parts of the truck and trailer. Each connector has seven terminal contacts. Common practice for attaching the receptacle""s terminal contacts to the wire conductors is accomplished by either:
1) attachment by inserting copper conductor into a hole centered at back end of the terminal contact and securing in place by tightening a screw tapped at a right angle to the hole; or
2) by crimping a bullet-type female disconnect terminal to the copper conductor and connecting it to the receptacle contact back end, which was machined into the form of a male bullet terminal.
The above-described connectors were generally satisfactory until the Department of Transportation (DOT) of the United States Government mandated that all new trucks exceeding 10,000 pounds must have anti-lock braking systems (ABS). The addition of ABS required that certain conductors carry more power, and preferably a larger size seven-conductor cable. However, the original SAE (Society of Automotive Engineers) seven-way receptacles were not designed to accommodate the larger size cable. The industry argued with the DOT that to change the large numbers of existing vehicles to a new receptacle design would be extremely costly. The DOT then agreed to permit a smaller size cable for activating the ABS.
Because of the undersized cable, overheating of the contacts soon became a problem, which was exacerbated, and this was increased with the introduction of new road solvents to break up ice. The overheated contacts and the new solvents rapidly induced corrosion. In some incidents, the heat at the corroded contacts became so intense that fires broke out.
Thus, it appears that there is a need for a connector or receptacle which will fit existing plugs and which is interchangeable with any standard SAE J560 b receptacle, but which is not subject to the excessive heating and corrosion described above.
The applicant has dealt with the above problems by redesigning the receptacle without increasing its size and without increasing the size of its contacts. This has involved two primary changes in the receptacle.
First, the resistance at the contacts has been substantially reduced by better attachment of the contacts to the conductors. Rather than using the screw-type or bullet-type connections, the contacts are crimped or soldered to the conductors.
Second, the receptacle itself is redesigned to be interchangeable with the standard J560 b plug, but two of the conductors have been increased in size to handle the increased automatic braking system (ABS) current load. The ground conductor was increased from a maximum 8 American Wire Gauge (AWG) to a 6 AWG; and where deemed necessary, the ABS designated conductor was increased from a 10 AWG to an 8 AWG. All the contacts and conductors are injection molded into a high temperature thermoplastic inner body, which protects the contact/conductor terminations from moisture and solvents. It will be recognized that thermoplastic covers a large range of materials, including PVC, TPE, polycarbonate, ABS, etc.
Additional features of this invention were also achieved during its development and are described in detail below but may be summarized.